Method and apparatus for burning combustible fluids



GQL. REICHHELM..

METHOD AND APPARATUS FOR BURNING COMBUSTIBLE FLUIDS. APPLICATION man JULY 13. ml.

1 ,3 1 0,928. Patented July 22, 1919.

2 SHEETSSHEET I. 6

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METHOD AND APPARATUS FOR BURNING COMBUSTIBLE FLUIDS. APPLICATION FILED JULY 13. 1911.

,3 1 0,928, Patented July 22, 1919.

2 SHEETS-SHEET 2.

Rae-762% W I. J w v e1; mwim METHOD AND APPARATUS FOR BURNING COMBUSTIBLE FLUIDS.

Specification of Letters Ratent.

Application filed July 13, 1917. Serial No. 180,299.

To all whom it may concern:

Be it known that I, GEORGE L. Rerou- HELM, a citizen of the United States, and resident of New Haven, in the county of N ew HaveffandState of Connecticut, have invented certain new and useful Improvements in Methods and Apparatus for Burn.- ing Combustible Fluids, of which the following is a specification.

My invention relates to improvements in methods and apparatus for burning combustible material, more particularly self-combustible gaseous mixtures, such as mixtures of combustible liquids, either as vapor or as a fog or spray, permanent gases or suspensions of combustible solids such as coal dust and air in the suitable proportions for combustion.

My improvements are applicable to burners for various purposes in which the heat of combustion is employed to heat other substances and also to burners for gas turbines and the like, in which the heat of combustion is utilized for increasing the kinetic energy of the gas molecules prior to their projection upon the blades of a turbine, and

forv other uses which will be apparent to.

those skilled in the arts In burning oils it has been found advisable to avoid smoke and for other reasons to mix the oil vapor or liquid in the form of a fog or spray with air to form a self-combustible mixture before combustion and this involves carrying out the combustion in such a way as to prevent the flame striking back to the point of admixture of the air and combusti ble.

It is also desirable to adopt the same method for burning more or less permanent gases such as water or coal gas as it enables the gas to be burnt in the smallest space at the highest rate of speed.

If the flow of self-combustible mixture is too slow the flame strikes back, if it is too rapid the flame will flow away from the ordinary orifice and go out unless special provision is made, for example, for retarding the stream by means of a baflie which reduces the velocity of flow and heats up the oncoming particles of gas or oil bringing them to ignition temperature.

I have found however that it is possible to obtain the desired results by passing the self-combustible mixture through an orifice of special form,

The problem of burningself-combustible gaseous mixtures is largely one of control of velocity of flow of the mixture with relation to the velocity of flame propagation.

It has been found, however, that the velocity of flame propagation increases as the area of cross-section of the space in which combustion occurs, increases and also increases as pressure of the gases decreases. If a self-combustible mixture of gases is forced through an outwardly flaring orifice the pressure drops from the throat of the orifice outwardly while at the same time the crosssectional area of the orifice increases. The velocity of flow of the gases also increases from the throat outwardly but it is found that under proper conditions the velocity of flame propagation increases at a more rapid rate owing to the increasing area of crosssection of the orifice and the decreasing gaseous pressure. It is possible therefore by adjusting the velocity of flow of the mixture through an outwardly flaring orifice to obtain combustion of the mixture within the orifice without the flame striking back through the throat of the latter.

With an outwardly flaring orifice the outer portions of the stream of flowing gases are checked by friction with the atmospheric air so that even if the velocity within the orifice is at all parts greater than the velocity of flame propagation the gases will burn in close proximity to the mouth of the orifice.

The point where combustion can take place most usefully depends upon the purpose for which the gas is burnt. In the case of a gas turbine the combustion should take place within the orifice or nozzle in order to take advantage of the expansion due to the heat of combustion in increasing the velocity of flow of the gases. In the case of a burner for heating a boiler or other purposes the combustion may to advantage take place outside the orifice to prevent an excessive amount of heat being transferred to the walls of the orifice instead of to the surface Patented July 22, acre.

to be heated which not only reduces *the' available heat but also tends to shorten the life of the burner.

In order to avoid deterioration of the material of the burner and to utilize the heat which might otherwise be lost by radiation,

conduction or other 'means I prefer to provide means for cooling the walls of the orifice by means of water or other cooling medium. In the ordinary 'uncooled burner if a combustible mixture is passed through the orifices at a high rate of speed and against a substance which becomes highly heated, then the radiant heat from such substance, apart from the heat obtained directly from the flame, will cause the burner to heat up and any free oxygen will combine to form rust or other oxid. At high temperatures this combination may take place to such an extent asto virtually burn the iron or other metal of the burner.

The principal objects of my present invention are to provide an improved method and apparatus for burning combustible material, to provide an improved method and apparatus for burning self-combustible gaseous mixtures, to provide an improved form of burner which will not be appreciably deteriorated by*the heat of the flame, to provide means whereby a burner may be made of easily oxidizable, easily fusible or other- 1 wise ordinarily undesirable material, to provide means. for artificially cooling the burner, to provide means for utilizing the heat transmitted to the burner by the flame either directly or indirectly, to provide means for burning a self-combustible gaseous mixture without the use of battles or the like or without the use of pilot flames or similar devices to maintain combustion, to provide means for burning gases pro jected through an orifice at a velocity greater than the velocity of flame propagation without splaying two jets against each other or other similar means for retarding the veloclty offlow of the gases, and generally to improve, simplify and cheapen the methods and apparatus employed for burning combustiblematerial.

In attaining these and other objects and advantages to be hereinafter set forth I have provided a construction, various embodiments of which are illustrated in the accom-- .panying drawings, in which:

Figure 1 IS a s1de elevat1on of a burner constructed in accordance with my present invention Fig. 2 1s a plan view of the same;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a detail view illustrating the relation of the flame to the burner;

Fig. 5 is a plan view of a modified form of construction;

Fig. 6 is a section on the line 6-6 of Fig.5; 1

Fig. 7 is a section on the line 77 of burner Fig. 10 is a longitudinal section on the line 1010 of Fig. 9;

Fig. 11 is a diagrammatic section through a water-tube boiler equipped with my improved burner, and,

Figs. 12 and 13 are respectively end views of burners of my invention showing means for causing flames to' encircle the tubes.

Referring to the form of construction shown in Figs. 1 to 4, air is forced in through the pipe 1 and gas through the pipe 2. The rate of flow of air and gas can be controlled separately by means of the valves 3 and 4. The mixture of air and gas is introduced into the burner 5 by means of the pipe 16. Both the air and the gas are preferably introduced under pressure as it enables larger quantities of gas to be burnt than if a gas injector is employed to draw in the desired air from the atmosphere as in the ordinary cook stove burner.

The burner 5 comprises a metallic shield or curved plate 6 and a series of tubes 7 arranged between two manifolds 8 and 9. The plate 6 is arranged to contact with the manifolds at each end and the outer pair of tubes 7 along its side edges so that the gases are forced to escape through the narrow slits 10 between the tubes 7. The spac between the plate 6 and the tubes 7 is su ciently large to supply gas to all of the slits between the tubes. ater or other cooling fluid passes into the manifold 8 by the connection 11, flows through the tubes 7 into the manifold 9 and out through connection 12 or Vice versa. By this means the temperature of the tubes can be readily kept at, or below, 212 F. so that they will not warp or deteriorate under the heat of the flame.

The gases passing through the slits 10 which act as outwardly flaring orifices, burn as indicated at 13 in Fig. 4:. The greater the velocity .of the stream of gas projected through the slots 10, the greater will be the sub-atmospheric condition created near the base of the flame. Gases flowing through such an orifice tend to spread out due to capillary attraction. If the flame is spread slightly, then the counter currents of air that even if the main gas stream is flowing at a velocity greater than the velocity of flame propagation, the parts 13 may have a velocity lower than the velocity of flame propagation and will therefore remain ignited and in turn heat up and finally ignite the rest of the stream 'which will. burn where its velocity 'is checked sufliciently.

with flame orifices between each tube. The

manifolds 8 and 9 are similar in construc-,

tion to the manifolds 8 and 9.

In Figs. 9 to 11 are shown applications of, my improved burner to: a fire-tube and water-tube boiler respectively.

The fire-box of a 'fire-tube locomotive boiler is illustrated diagrammatically in Figs. 9 and 10. A series of tubes 18 are provided for the passage of the products ofv combustion from the burner 5 which is of the same type as that shown in Figs. 1 to 4. The flames from the burner play on the up per surface 19 of the fire box and passforwardly and then up the front of the boiler and back along the tubes 18. Waterfor the tubes 7 of the burner is drawn from the boiler by pipe 20 and returned to the'boiler either as water or steam by the pipe 21. A water-tube boiler is illustrated diagrammatically in Fig. 11. Inthis case the burner is of the circular type shown in Figs. 5 to 8 and the water tubes 22 are arranged in a spiral around the burner. These tubes are substantially in contact with each other so that the products of combustion from the burner are compelled to follow the spiral path between the series of water tubes. Preferably the water tubes are arranged horizontally and the water isarranged to pass from the outer end of the spiral progressively toward the center by passing forward along one tube then back along the adjacent tube and so forth. When the water or steam as it will be when it reaches-the center of the spiral, passes out of the last water tube it passes into the tubes 7* of the burner so that the burner will act as a superheater for the steam.

4 passing 26 for causing the flames to encircle the tubes to increase the heat efficiency. In Fig.

13 the inner set 27 and outer set 28 of tubes are so relatively arranged as to cause the flames to encircle the tubes 28.

. Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is:

1. A burner comprising in combination a pair of exteriorly arranged cylindrical members in close proximity to each other, and means for forcing a gaseous mixture through the space between said members.

2. A burner comprising in combination a pair of tubes in close proximity to each other and forming a-fla-ring orifice, means for forcing a' combustible mixture through the space between said tubes, and means for a cooling medium through said tubes.

3. A burner comprising a pair of manifolds, an annular series of tubes therebetween, means for forcing a combustible mixture into the space confined by said tubes and out through the spaces between said tubes, and means for passing a cooling medium through said tubes and manifolds.

4. A method of burning combustible 'gaseous mixtures comprising projecting the mixture through an orifice at a velocity greater than the rate of flame propagation, gradually reducing the velocity of the entire mixture and which further includes reducing the velocity of flow of a part of the gaseous stream below the velocity of flame propagation.

5. A burner comprising in combination a pair of exteriorly arranged tubes in close proximity to each other and formin a flaring orifice, means for forcing a com ustible mixture through said orifice, and means for passing a cooling medium through said. 

